The present invention generally relates to the art of knitting, and more specifically to a method and knitting machine arrangement for knitting on a circular knitting machine utilizing stacked pattern wheels at feeding stations and selective placement of needles having high and low butts.
The knitting machine art is an old one and numerous approaches have been proposed and used to knit fabrics having desired patterns or designs.
A frequently used knitting machine is the circular knitting machine which utilizes pattern wheels each of which is programmed to correspond to a desired effect in the finished fabric. The pattern wheels are, therefore, in the nature of storage devices which store pattern data and engage and cooperate with associated knitting needles to position the same in desired positions in the knitting process at preselected periods of the knitting cycle. The manner in which circular knitting machines operate, and the manner in which the pattern wheels actuate knitting needles is well known to those skilled in the art. Illustrative of the state of the art in this respect include the following U.S. Pat. Nos.: 2,006,821; 2,008,810; 2,055,598; 2,055,599; 2,203,711; 2,539,790; 2,627,172; 2,941,383; 3,274,800; 2,457,736 and 3,858,414. Other patterning mechanisms for circular and other knitting machines are also known, some illustrative U.S. patents in this area being as follows: Nos. 2,928,266; 3,077,756; 3,166,920 and 3,167,939. A problem which has existed with some prior art circular knitting machines is the limitation of the pattern area, namely the relatively limited number of knitting needles which may be controlled during each repeat of the preselected pattern. Furthermore, in some prior art machines, the pattern must be repeated each time the pattern wheel completes one revolution.
Aside from the above-described problem relating to pattern width, many circular knitting machines pose the additional problem that unless the number of slots provided in the pattern wheels bear a certain relationship to the number of needles inserted in the cylinder of the machine, successive patterns occur with a shift therebetween. Specifically, unless the number of needles divided by the number of slots in the pattern wheel is a whole number, a shift occurs since the pattern wheel rotates less than a whole number of times relative to the needles. The shift that occurs in the pattern becomes more pronounced and usually is more objectionable in utilizing the fabric for preparing articles, such as garments, and the like. The fabric made with a pattern shift, known as spiraling, is limited in its versatility and usefulness for making garments since the position of the pattern must be taken into account in cutting the fabric.
With single knit machines which utilize one pattern wheel per knitting station, the pattern has to be repeated after each turn of the pattern wheel, producing all-over patterns. To give any height to the pattern, the pattern is divided in the wheel and through an uneven number of pattern wheel turns with relation to the needles in the cylinder, parts of the divided pattern in the wheel repeat above the other parts producing the effect of a taller but thinner pattern on the knitted cloth. This system produces, however, the patterns in a spiraling fashion as suggested above. Single knit Jacquard machines produce cloth using three positions of needle height. The normal knit and miss positions produce the pictorial pattern and the tuck position "ties" the yarns that are floated across the back into the cloth. Double knit machines with large Jacquard design mechanisms other than pattern wheels are capable of placing the patterns and producing a pattern with no spiral. These machines use two positions, knit and miss, to produce the design and the yarns floated between the knit areas are knitted into the cloth on the second bed of needles.
Single knit pattern wheel machines have been the only practical means of producing Jacquard patterns on knitted cloth because of their three position capability, but heretofore could only make all over spiraling designs.
The flexibility of a circular knitting machine to generate quality knitted fabrics having desired patterns or designs is to a great extent a function of the gage of the machine and the ability of the machine to control a large number of knitting needles during each repeat of the pattern. An early attempt to achieve an enhanced fineness of stitching is disclosed in U.S. Pat. No. 2,030,815 for a "Knitting Machine" to Feineman. This patent discloses a circular knitting machine having a plurality of banks of needles with cams or butts at different levels, each of which bank of needles cooperate with a corresponding bank or series of pattern wheels. While Feineman discloses the use of stacked pattern wheels at a feeding station, this is specifically for the purpose of providing a wider range of regulation of tightness or looseness of the stitch without excessively decreasing the tightness of the vanes or teeth of the pattern wheels which would weaken the teeth and possibly result in their becoming damaged during operation.
An attempt to provide a knitting machine which produces patterns which are not shifted vertically or horizontally, but in alignment in these directions, was described in U.S. Pat. No. 3,122,905 entitled "Knitting Machine" to Gutschmit. Another object of the Gutschmit machine was to permit several patterns to be simultaneously knitted during each revolution of the cylinder, each of which patterns may extend through several revolutions. To achieve these objects, the Gutschmit Knitting Machine utilized long and short needles which were carried on a rotatable cylinder of the machine. The needles were adapted to be raised separately and in synchronism therebetween by slotted pattern wheels disposed in their rotating path. The slots of the pattern wheels were filled with jacks or left empty for forming a pattern. In addition, since the long and short needles knit separately, one set of needles could be made to be operative over the knitting period when the other set of needles could introduce the shift, so that the shift did not occur. Alternately, a pattern with a shift could be produced, if desired, by selecting a combination of long and short needles. However, in order to achieve his objects, Gutschmit had to use special jacks slidably mounted within the cylinder slots or stacked cylinders as disclosed in the Gutschmit patent. A cylinder having a double height was required, this clearly increasing the expense of manufacturing the Gutschmit Knitting Machine as well as complicating its construction, operation and maintenance.
Another attempt to provide a needle selecting device for patterning knit fabrics which remains unaltered during the operation of the knitting machine which provides a pattern area of knitting needles is described in U.S. Pat. No. 3,145,548 for "Pattern Mechanism for Circular Knitting Machines" to Mishcon. The Mishcon knitting machine included a circular arranged bank of evenly spaced knitting needles divided into groups having common-height butts. Three pattern wheels were stacked at a feeding station, each pattern wheel being arranged to engage one of the groups of knitting needles. More specifically, the highest pattern wheel on the stack being arranged to engage the highest butt needles, the lowest pattern wheel being arranged to engage the lowest butt needles and the intermediate pattern wheel being arranged to engage the intermediate butt needles. In order to enlarge the pattern area, Miscon required that each of the pattern wheels have a total number of jack accommodating slots which was not divisible exactly by any prime factor of the number of groups of knitting needles. However, the only way that Mishcon could use all the slots in the pattern wheels was to make an odd number of slots as noted. With the arrangement disclosed, Mishcon only teaches knitting of fabric having a uniform allover design or pattern which is wider than could normally be achieved with a single pattern wheel. However, Mishcon does not discuss the possibility of spotting a fabric or knitting two separate and distinct designs on selected portions of the fabric.
The present invention also utilizes stacked pattern wheels at each feeding station but overcomes the above-noted disadvantages inherent in the prior art knitting machines. The knitting machine of the present invention makes it possible to produce two patterns instead of one and to be able to place each pattern wherever desired. This can be achieved in a simple and inexpensive manner and does not require knitting machines having excessively high cylinders. In the present invention, it is also possible to produce two patterns and join them, by placement, to produce one pattern which is larger than the ones previously produced, and the resulting pattern does not exhibit the undesirable spiral effect. Additionally, the knitting machine of the invention makes it possible to place a pattern upon a plain background (which is actually another pattern) to achieve the effect of spotting the pattern in any desired manner along a vertical or longitudinal direction of the cloth.